This invention relates generally to devices and methods for drawing milk from a human breast.
Many mothers rely on pumps to extract their breast milk. The more such pumps are automated and simulate the natural sucking rhythms of an infant, the easier it can be for a mother to relax and allow her milk to xe2x80x9clet downxe2x80x9d and flow. Pumps in common use include manually operated mechanical pumps, which require the user to repeatedly manipulate a lever or pedal to produce suction, and electrical pumps, which run on either DC battery or AC line voltage.
With portable pumps, especially ones with electric vacuum sources, it is preferred that the milk only enters the easily washed storage bottle connected to the breast hood. Particularly, milk should be kept from inaccessible vacuum passages and pumping hardware which is not easily cleaned. Many electric pumps, for instance, come with instructions that caution against allowing the pump to tip over or lie on its side with milk in the bottle, as the milk may flow through the vacuum port and into the pumping chamber.
According to one aspect of the invention, a receptacle bulkhead for a portable pumping device for drawing milk from a human breast is provided. The pumping device has a milk receptacle and a vacuum source for applying suction to a hood configured to receive the breast, and the receptacle bulkhead is configured to separately connect the vacuum source and the hood to the milk receptacle. The bulkhead has a housing defining an internal chamber, a milk inlet conduit, a milk outlet conduit and a vacuum port. The milk inlet conduit provides communication between the hood and the internal chamber and extends from one side of the internal chamber with the portable pumping device in an upright position for normal use, such that entering milk tends to flow along a lower side of the conduit. The milk outlet provides communication between the internal chamber and the milk receptacle, and is disposed at a lower end of the internal chamber with the portable pumping device in its upright position. The vacuum port provides communication between the vacuum source and the internal chamber through a vacuum inlet passage within the receptacle bulkhead. The vacuum inlet passage extends a distance along the milk inlet conduit and is separated from the lower side of the conduit, such that with the pumping device in its upright position milk entering from the hood will tend to avoid the vacuum inlet passage and, with the pumping device in a sideways position with the milk inlet conduit extending upward, milk from the receptacle will be inhibited from entering the vacuum inlet passage.
In a presently preferred construction, the internal chamber has a domed upper surface and the vacuum port is disposed at an upper apex of the domed upper surface.
The housing may be of a unitary molded piece of transparent plastic, for example, and may form a top for the milk receptacle, with the milk outlet making a threaded connection between the milk receptacle and the bulkhead housing.
Preferably, the vacuum inlet passage extends beyond the milk outlet toward the hood.
According to another aspect of the invention, a breast pump for drawing milk from a human breast includes a hood configured to receive the breast, a milk receptacle in communication with the hood for storing milk from the breast, a vacuum source for applying suction to the hood, and a one-way valve disposed between the hood and the milk receptacle. The valve includes a cup-shaped valve body with a hole through its bottom, and a flexible membrane flap. The flap is arranged to cover the hole through the valve body when suction is applied to the hood, inhibiting flow between the hood and the milk receptacle, such that milk from the hood is collected in the cup on top of the membrane flap, and to flex, under weight of the collected milk, to expose the hole when hood suction is released, allowing the collected milk to flow from the valve body into the milk receptacle.
In one preferred embodiment, the valve cup is retained in a bulkhead constructed to provide communication between the hood, the milk receptacle, and the vacuum source, with the valve cup engaging the bulkhead at an interface constructed to provide a predetermined amount of air leakage around the valve, between the bulkhead and the milk receptacle, when suction is applied to the hood.
According to another aspect of the invention, a breast pump for drawing milk from a human breast includes a hood configured to receive the breast, a milk receptacle in communication with the hood for storing milk from the breast, a vacuum source for applying suction to the hood, a bulkhead constructed to provide communication between the hood, the milk receptacle, and the vacuum source, and a one-way valve disposed between the hood and the milk receptacle and engaging the bulkhead at an interface. The valve is constructed to close when suction is applied to the hood, and to open when suction is released to let collected milk flow into the milk receptacle. The interface between the valve and the bulkhead is constructed to provide a predetermined amount of air leakage around the valve, between the bulkhead and the milk receptacle, when suction is applied to the hood, for transferring vacuum to the milk receptacle during suction for pulling collected milk into the milk receptacle when suction is released.
Other aspects of the invention include methods of using the above-described pumping devices to extract milk from a human breast. For example, the method of using the pumping device of the first aspect of the invention includes holding the hood of the pumping device against the breast, and activating the pumping device to begin applying repeating pressure cycles to the breast to extract milk. The controller of the pumping device regulates the frequency and intervals of the pressure cycles to be effectively independent of suction, flow rates and power levels.
The improved bulkhead design of the invention can help to avoid milk entering the main body of the pump and pumping chamber, facilitating cleaning. Other features and advantages will be apparent from the following embodiment description.